Evaporator header construction



Nov. 16, 1943. 5, c. JOHNSON EvAPdRATon HEADERCONSTRUCTION 2 Sheets-Sheet 1,

Filed April 4, 1941 V5 U BERNAPDC JoH/vso/v B. C. JOHNSON EVAPORATOR HEADER CONSTRUCTION Filed April 4, 1941 2 Sheets-Sheet 2 Nov. 16, 1943.

frllvli VE 559M120 C Jo/W5 0A/ Patented Nov. 16, 1943 UNITED STATES PATENT OFFICE.

EVAPORATOR HEADER CONSTRUCTION Bernard C. Johnson, Ilihertyville, Ill., assignor to Houdaille-Hershey Corporation, Detroit, .Mich.. a corporation of Michigan Application April 4, 1941, Serial No. 386,855

Claims. (Cl. 62-126) This invention relates to evaporators or heat exchangers having-divided header chambers.

More specifically the invention relates to sheet metal evaporator units havingchambers with baffles or dividing Walls-therein for separating the chambers into a plurality of compartments.

In mechanical refrigerator systems it is highly desirable to utilize as much of the'heat absorb-.

off or gasify in the evaporator unitthere is a tendency for unspent refrigerant to be entrained with the spent refrigerant gases or vapor as the same pass through the return tube to thecompressor thereby 'cooling this tube and causing frost to form on the exterior of the tube.

a In accordance with the present invention the entrainment of unspent refrigerant with the gases or vapor in the return tube is completely eliminated or. minimized by dividing the header chambers of the evaporator unit into a plurality of compartments which successively receive the, refrigerant so that, by the time the refrigerant reaches the return tube, it is completely spent.

A feature of the invention resides in the pro-.

vision of a vertical baffle plate. in the header chamber of an evaporator unit to divide the chamrator unit shown in Figure 1.

her into two compartments one of which receives an evaporator unit havinga mum-compartment header chamber.

Another object of the invention is to provide a header construction for evaporator units with a dividing wall or baflle separating each header chamber into a pluralit of compartments.

A specific object of the invention is to provide sheet metal evaporatorunits having embossed portions defining a header chamber with a sheet metal dividing wall between the embossed portions for forming therewith a multi-compartment chamber.

Another object of the invention is to sandwich a sheet of metal between the walls of a sheet metal evaporator unit for extending across embossed portions of the unit to divide the chamber provided by said embossed portions into a plurality of compartments.

Another object of the invention is to divide a single header chamber in an evaporator unit 7 into a liquid-receiving compartment and a gasreceiving compartment for preventing discharge of unspent refrigerant from the unit.

Other and further objects of the invention will become apparent to those skilled in the art from the following detailed description of theannexed sheets of drawings which, by way of example,

illustratea preferred form of the invention. It will be understood that the invention is not limited to. theillustrated preferred form since the construction can bevaried greatly without departing from the scope of the invention.

On the drawings:

Figure 1 is a rear end elevational view of a sheet metal evaporator unit having a header construction according to this invention.

Figure 2 is a side elevational view of the evapo- Figure 3' is a fragmentary enlarged side elevational view of the evaporator unit shown in Figures 1 and 2 and better illustrating the header construction of theunit.

Figure 4 is a horizontal cross-sectional view taken along the line IVIV of Figure 3.

Figure 5 is a vertical cross-sectional view taken along the line VV of Figure 3.

Figure 6 is a broken side elevational view of the baliie or dividing wall mounted in the header construction of this invention.

As shown on the drawings:

In Figures 1 and 2, the reference numeral In designates generally an evaporator unit composed of aninner metal sheet II and an outer metal sheet l2. The sheets H and i2 are secured together by brazing, spot-welding, stitchwelding or the like. The evaporator unit I0 is U -shaped as best shownin Figure 1 to define the side walls and bottom of a sharp freezing cham ber 13. A shelf l4 composed of sheet metal is mounted in the sharp freezing chamber and bridges the space between the side walls. It can be'provided with downturned flanges lda at' the side edges thereof receiving rivets i5 therethrough which also extend through th side walls'of the unit to fixedly unite the shelf to the unit.

Thetop ends of the side walls can be bent hori zontally inward to provide horizontal flanges I6 I gases and will collect in thebottomor the comtending outwardly from the embossments H as M best known in Figures 1, 4 and 5.

ant entrainedwith the gases will be completely vaporized or gasifled in the compartment 23 since these compartments are in heat exchange relation with the sharp freezing chamber i3 and the unspent refrigerant will absorb heat from the chamher. In the event that appreciable amounts of unspent refrigerant are splashed over into the compartment 23 thesame will be heavier than the partment'suntll completely gasifle'd.

The passageways provided by the flute 21 therefore should only receive spent refrigerant which is removed from the unit through the ducts pro- The inner sheet II has complementary rec.-.

tangular embossments i9 and semi-cylindrical embossments 20 registering with the embossments I i i and i8 respectively.

In accordance with this invention and-as best vided by theflutes 21 and 29. The outlet tube 30 therefore only receives completely spent refrigerant.

Since thespent refrigerant gases have an appreciable length of travel while still retained in shown in Figures 4 to 6, a substantially rectangu lar metal plate 2i is sandwiched between the sheets ii and i2 and fitted into rectangular embossments i1 and-elect these sheets. The plate extends vertically through the chamber provided by the embossments II and as best shown in Figure 5 to divide this chamber into. compartments 22 and 23. I i

The plate 2| has an aperture 2ia therethrough Q near the top thereof at the end of the plate which is positioned adjacent to the front end of the.

evaporator I0 as best shown in Figures 3 and-i.

; It will, of course, be understood that a similar plate 2i is provided in the other walls of the evaporator unit to divide the other chamber into a pair of compartments 22 and-23.

- The outer sheet of the unitiii has aplurality of spaced flutes 24 embossed therein providing refrigerant circulating ducts or passageways communicating'at their upper ends with the bottom offthe compartment 22 of eachheader chamber. A flute 25 is embossed in the bottom wall' portion of the outer sheet l2'to Provide an inlet manifold to the ducts defined by'the' flutes 24. Liquid refrigerant is supplied to' this inlet maulfold through a tube 28 entering the rear end of the flute 25 as best shown in Figures 1 and 2. Refrigerant thus circulates from the inlet tube through the ducts provided by the flutes 24 and 25 along the bottom and side walls of the unit to the compartment 22 of each header chamber.

The inner sheet Ii is further embossed as t 2? to provide passageways extending from the rear upper end of each header compartment 23 toward the rear end of the unit. These passageways communicate with a-retum passagewayprovided byan embossed flute 28 onthe outer: sheet i2, which extends around the side andpbottom walls of the unit as best shown in Figures .1 and 2.

The bottom wall portion of the inner sheet I I is embossed as at 29 to provide a passageway communicating with the bottom portion of. the passa eway formed by the flute 28', as shownin Figure 1. An outlet tube 30 is secured tothe flute 29 and communicates with the passageway. Refrigerant supplied to the ,compartments. 22 of the header chambers by thedistributing ducts 2t isnot allowed to reach the level of the openings 2ia in the plates 21. Therefore these openings 2ia only communicate withthe gasspace above the liquid refrigerant in the compartments 22.

As the refrigerant boil 011- or gasifles inithe compartments 22 the gas can enter the compartments 23 of the header chambers through the opening 2ia and any unspent or liquid refrigerthe-evaporator-unit because they must pass through the ducts provided by the flutes 21, 28 and28, any residual cooling capacity of the gases is absorbed by the unit.

As a result, the outlet tube II can never become 'cool enough to be frosted, and no frost back is provided in systems using evaporator units of this-invention; I l

From the above description it will be understood that the invention now provides a heat exchangerespecially adapted to be made or sheet metal and containing at least one header chamber which is divided by a baiile intoa plurality of compartments which successively receive fluid circulated through the'exchanger.

Iclaim as'my invention: I l. A U-shaped sheet metal evaporator unit having the constituent'sheets' thereof embossed,

to provide aheader'chamber in each leg-of the unit, a plate between the sheets dividing the chamber into communicating-compartments; embossments on the innersheet-deflning ducts communicating. respectively,with' one of said compartments in said header chambers. and anadditional embossment providing a passageway conimunicating with said'ducts to exhaustspentrefrigerant from said, compartments.

; 2. A sheet metal U-shaped evaporator 'unit comprising a pair of secured-together contiguous metal sheets, said-sheets being embossed to define a header chamber extendingtransve'rsely across each leg of'the unit, said outer sheet being further embossedto deflne a plurality of spaced parallel refrigerant circulating I ducts connecting said header chambers, a baflle plate between the sheets in each leg of the'unit dividing the; header chambers into :a pair of compartments, each baflie plate havingan aperture therethrough'joinheader chamber extending transversely along each leg of the unit, a baiile plate in each leg of the unit between the sheets dividing each header chamber into'inner and outer'compartments, said outer sheet being further embossed to definea plurality'of spaced refrigerant circulating-ducts connecting the outer compartments, at least one of said sheetsbeing further embossed to define a spent refrigerant outlet passageway connecting the upper portions of the inner compartments, and an exhaust tube communicating with said passageway at a p int remote from both inner compartments.

4. In a heat exchanger having a header cham: ber adapted to contain liquid refrigerant and provided with an outlet opening at one end, the improvement which comprises a partition dividing said chamber lengthwise into two compartments extending side by side, said'partition being capable of preventing flowof liquid refrigerant between the compartments, said partition further having a. top portion apertured at a point spaced widely from said outlet opening, whereby any fluid flowing through said aperture and thence through one of said compartments to said outlet is forced to move for a considerable distancelengthwise of said header chamber.

5. In a heat exchanger having a header chamber, the improvement which comprises a partition dividing said chamber lengthwise into two compartments extending side by side and intercommunicating solely at the top of one chamber end so as to form a U-shaped path for gasifled refrigerant superimposed on two separate elongate liquid refrigerant'spaces'extending in the same general direction as the legs of said U.

6. A sheet metal U-shaped evaporator unit comprising a pair of secured-together contiguous embossed metal sheets and metal plates. between portions of the sheets cooperating for defining inner and outer header chamber compartments in each leg of the unit, at least oneof said sheets being further embossed to define a spent -refrigerant outlet passagewayconnecting the upper portions of the inner header compartments. the bottom of the other sheet being embossed above said passageway to continue the same. and an exhaust tube communicating with the continuacates with the ducts and the other of which combefore entering the exhaust tube to eliminate frosting of the tube.

8. The method of preventing frost back of th exhaust tube in a mechanical refrigerating system which comprises flowing liquid refrigerant into one compartment of a multi-compartment header chamber ahead of said exhaust tuberctainlng the liquid refrigerant in said one compartment while evaporating the liquid. and suc cessively flowing the gasifled refrigerant through said one compartment and thence through anflowing the gasified refrigerant through a heat exchange zone spaced from the collected refrigerant, and trapping in said zone any liquid refrigerant entrained by the gasifled refrigerant, whereby the gasifled refrigerant will absorb sufficient heat before entering said return tubes not to frost the same.

10. In an evaporator structure shaped to provide a plurality of refrigerant ducts and an elongated header chamber in communication with 'said ducts to receive refrigerant therefrom, said structure having a refrigerant inlet communicating with said ducts and an exhausted refrigerant outlet communicating with the upper portion of said chamber at one end thereof, the improvement of a bailie in said heater chamber dividing the chamber lengthwise thereof into two separate compartments one of which communim'unicates with the outlet, and said bailie having a passageway therethrough joining the upper portions of said compartments only at the end of the header chamber which is remote from the outlet end whereby liquid refrigerant is prevented from reaching said outlet,

BERNARD C. JOHNSON.

frigerant can be made to absorb sufficient heat 

